Take a look on youtube for the 99XX's disassembly and assembly video's.
It's pretty straight forward and easy to do so. Just be gentle and take your time.
I would also really like help on this topic. Some of the cheaper housings dont have the antennas and such attached so is it possible to buy on of these and insert my chassis into the new backplate?? Or is there a way to remove every antenna and component from the old backplate into the new? Thanks